基于纳米划痕的页岩纹层矿物组分识别

Mineral Component Identification of Shale Bedding Based on Nano Scratch

  • 摘要: 利用扫描电子显微镜对古龙页岩划痕试验中的损伤形态和矿物成分进行了分析,采用高斯函数曲线拟合划痕试验获得的划痕深度、d2-L曲线的斜率、断裂韧性等力学参数,以确定矿物含量。结果表明:基于划痕试验对矿物组分的识别与扫描电镜结果存在差异,主要归因于页岩本身非均质性和孔隙与微裂纹发育所导致。基于划痕深度识别矿物较为便捷,但此方法很难区分裂缝与较软有机质。d2-L曲线斜率识别结果准确性受矿物非均质性影响显著,白云石在塑性矿物与脆性矿物分布区域内无法被准确识别。断裂韧性法避免了孔隙和裂纹的影响,矿物识别结果与扫描电镜分析结果较为接近。

     

    Abstract: The damage morphology and mineral composition were analyzed during the scratch test of Gulong shale using SEM. Using Gaussian function curve-fitting to obtain mechanical from the scratch test, including scratch depth, slope of d2-L curve, and fracture toughness from scratch test, to determine the mineral component content. The results indicate that there is a certain difference between the identification of mineral components based on scratch tests and the results of SEM, which is mainly caused by the heterogeneity of shale itself and the abundance of pores and micro cracks. Although convenient to identify minerals based on scratch depth, this method is difficult to distinguish between cracks and soft organic matter. The accuracy of identifying the slope of the d2-L curve is greatly affected by mineral heterogeneity, and dolomite cannot be accurately identified in the distribution areas of plastic minerals and brittle minerals. The fracture toughness-based method avoids the influence of pores and cracks, and the identification results of minerals are relatively close to the mineral content of SEM.

     

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